1. Field of the Invention
The invention relates to an apparatus for the impedance matching of an electrical load to the source impedance of a generator wherein the apparatus has input connections for connection to the generator and output connections for connection to the load; wherein the apparatus has a converter, which connects the input connections to the output connections by means of which an input voltage, which is applied between the input connections, can be converted into an output voltage different from this voltage produced between the output connections; wherein the converter has an energy storage means, a controllable switching device which is connected to said energy storage means and an actuation device for said switching device; wherein the switching device is designed and can be moved to a first and a second switching state in such a way that energy from the generator can be stored in the energy storage means in the first switching state and energy which is stored in the energy storage means can be output to the load in the second switching state; and wherein the apparatus has a detector, which is connected to the input connections, for detecting a measurement signal for the impedance matching; wherein the actuation device has an activation input by means of which it can be moved to a first and a second operating state; wherein the actuation device is designed in such a way that the first switching state is avoided in the first operating state and a changeover is made between the switching states in the second operating state; and wherein the detector is connected to the activation input by way of its measurement signal output.
2. Description of Prior Art
Such an apparatus, which, as a generator, has an antenna that outputs an alternating voltage in an electromagnetic field, is known from US 2009/0067208 A 1. The antenna is connected to an electrical load by means of an impedance-matching module, a rectifier module for converting the alternating voltage into a direct voltage, and a direct voltage-direct voltage converter. The direct voltage-direct voltage converter has, as an energy storage means, an inductor connected to a first connection with one output of the rectifier module and, with its second connection, to the load by way of a semiconductor diode and a controller module connected in parallel with said diode. The second connection can also be connected to ground potential by way of the controller module. A measuring device is provided for detecting a measurement signal for the output voltage of the rectifier module. In the measuring device, the output voltage of the rectifier module is compared to an upper threshold and a lower threshold. If the output voltage is above the upper threshold, the direct voltage-direct voltage converter is activated and if the output voltage is below the lower threshold, the direct voltage-direct voltage converter is deactivated. As the inductor is connected in the circuit before the impedance-matching module, the apparatus has a relatively complicated structure.
The object of the invention is, therefore, to create an apparatus of the aforementioned type that has a simple structure but still allows impedance matching of a load with a low loss to the source impedance of a generator having a broadband, nonharmonic output voltage in particular, in such a way that the said generator outputs a power that is as high as possible.